Traditional large heat chambers operate by delivering heat energy to materials by one or a combination of radiant heat, hot air convection or hot forced air. The configuration of the heat delivery mechanism is generally fixed by the chamber designer. The chamber users can usually only select heating time and temperature for a specific application. These parameters are determined experimentally by using instrumentation and running test loads of materials. This method is satisfactorily but may not produce as economical process as may be achieved using other methods.
A particular load configuration with a fixed airflow velocity and direction in forced hot air heat chambers often produces uneven heating with hot and cold spots. The hot and cold spots may be a significant issue when a product or process requires achieving a specific or a narrow allowable temperature band. In some instances a product may not achieve a proper dryness, temperature, consistency, condition, state or strength. This may require reheating a product, poor product preservation, unusable product, product loss or poor final product performance. In most cases, the input hot air temperature can be lowered to a level equal to, or just above, final maximum acceptable temperature and the heating time increased to prevent material in the hot spots from exceeding the maximum allowed. The heating time can also be adjusted to get the material in the cold spots up to the specified minimum temperature. These solutions may not be as energy efficient or produce the as good as results and might otherwise be achieved.